Electronic device

ABSTRACT

The present application relates to an electronic device comprising a hole-transport layer A, a doped hole-transport layer B and a hole-transport layer C, where hole-transport layers A, B and C are arranged between the anode and the emitting layer, and where hole-transport layer B is arranged on the cathode side of hole-transport layer A and hole-transport layer C is arranged on the cathode side of hole-transport layer B.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a national stage application (under 35 U.S.C. § 371)of PCT/EP2013/002727, filed Sep. 11, 2013, which claims benefit ofEuropean Application No. 12006991.9, filed Oct. 9, 2012, both of whichare incorporated herein by reference in their entirety.

The present application relates to an electronic device comprising ahole-transport layer A, a doped hole-transport layer B and ahole-transport layer C, where hole-transport layers A, B and C arearranged between the anode and the emitting layer, and wherehole-transport layer B is arranged on the cathode side of hole-transportlayer A and hole-transport layer C is arranged on the cathode side ofhole-transport layer B.

Electronic devices in the sense of this application are taken to mean,in particular, so-called organic electronic devices, which compriseorganic semiconductor materials as functional materials. These are againtaken to mean, in particular, organic electroluminescent devices (OLEDs)and other electronic devices which are mentioned below.

The structure of OLEDs in which organic semiconductors are employed asfunctional materials is described, for example, in U.S. Pat. No.4,539,507, U.S. Pat. No. 5,151,629, EP 0676461 and WO 98/27136.

In the case of the electronic devices concerned, in particular OLEDs,there is considerable interest in improving the performance data, inparticular lifetime, efficiency and operating voltage.

The efficiency and lifetime of electronic devices, such as OLEDs, aredetermined, inter alia, by the charge-carrier balance of electrons andholes in the device. This balance becomes established through thecharge-carrier distribution and the associated field distribution in thedevice.

For good performance data, good mobilities of the charge carriers in thehole-transport layers and good hole-injection properties areparticularly crucial. Furthermore, it is of crucial importance that thedifference of the HOMOs of the materials of the various hole-transportlayers is not excessive.

The prior art discloses the use of a p-doped hole-transport layer,followed by an undoped electron-blocking layer, between the anode andthe emitting layer (WO 20021041414). In this case, the p-dopedhole-transport layer is not followed by a further hole-transport layer,but instead directly by the emitting layer.

The prior art furthermore discloses the use of two or morehole-transport layers between the anode and the emitting layer (WO2010/094378).

On the basis of this prior art, the technical object is to provideelectronic devices, in particular OLEDs, which have improved performancedata, in particular in respect of lifetime and efficiency.

Surprisingly, it has now been found that the use of a p-dopedhole-transport layer between a first hole-transport layer and a furtherhole-transport layer, regarded from the anode, causes an improvement inthe above-mentioned points and thus achieves the technical object.

The present application thus relates to an electronic device comprisinganode, cathode and at least one emitting layer arranged between theanode and the cathode, and

-   -   at least one hole-transport layer A, comprising at least one        hole-transport material    -   at least one p-doped hole-transport layer B, comprising at least        one p-dopant and at least one hole-transport material matrix    -   at least one hole-transport layer C, comprising at least one        hole-transport material,

where hole-transport layers A, B and C are arranged between the anodeand the emitting layer, and

where hole-transport layer B is arranged on the cathode side ofhole-transport layer A, and hole-transport layer C is arranged on thecathode side of hole-transport layer B.

The electronic device according to the invention has the advantage thatit has higher efficiency, preferably combined with a longer lifetime.Furthermore, it can be operated at comparatively low voltage.

The device according to the invention furthermore has the advantage thatmaterials having a low HOMO can thus be used in a hole-transport layer,in particular in combination with materials having a higher HOMO inanother hole-transport layer.

The fact that, in accordance with the invention, only hole-transportlayer B has to be p-doped means that the amount of p-dopant required andthus the costs are lower compared with a structure in which allhole-transport layers are p-doped. This represents an advantage overdevices in accordance with the prior art in which all hole-transportlayers are p-doped.

A hole-transport layer for the purposes of the present application istaken to mean an organic layer which has hole-transporting properties.In particular, it is taken to mean an organic layer which is locatedbetween the anode and the emitting layer and has hole-transportingproperties. A hole-transport material is correspondingly taken to mean amaterial having hole-transporting properties.

A p-dopant is taken to mean a compound which is able to at leastpartially oxidise the other compound (the matrix) present in the layerand in this way increases the conductivity of the layer. p-Dopants inaccordance with the present application are typically organicelectron-acceptor compounds.

A matrix here denotes the compound or compounds which represent thepredominant component (% by weight) in a layer comprising a dopant.Correspondingly, the dopant represents the component present in loweramount in the corresponding layer. A corresponding situation applies tothe specific terms hole-transport material matrix and p-dopant.

The electronic device according to the invention is preferably selectedfrom organic light-emitting transistors (OLETs), organic light-emittingelectrochemical cells (OLECs), organic laser diodes (O-lasers) andorganic electroluminescent devices (OLEDs).

Particular preference is given to organic electroluminescent devices(OLEDs).

The anode of the electronic device preferably consists of a materialhaving a high work function. The anode preferably has a work function ofgreater than 4.5 eV vs. vacuum. Suitable for this purpose are on the onehand metals having a high redox potential, such as, for example, Ag, Ptor Au. On the other hand, metal/metal oxide electrodes (for exampleAl/Ni/NiO_(x), Al/PtO_(x)) may also be preferred. For some applications,at least one of the electrodes must be transparent or partiallytransparent in order to facilitate either the irradiation of the organicmaterial (organic solar cells) or the coupling-out of light (OLEDs,O-lasers). Preferred anode materials here are conductive mixed metaloxides. Particular preference is given to indium tin oxide (ITO) orindium zinc oxide (IZO). Preference is furthermore given to conductive,doped organic materials, in particular conductive doped polymers.

According to a preferred embodiment of the invention, the electronicdevice is characterised in that the anode comprises tungsten oxide,molybdenum oxide and/or vanadium oxide, and/or in that a p-dopedhole-transport layer A′, comprising at least one p-dopant and ahole-transport material matrix, is arranged between the anode andhole-transport layer A.

The above-mentioned anode comprising tungsten oxide, molybdenum oxideand/or vanadium oxide is preferably built up in such a way that itconsists of indium tin oxide (ITO) which has been coated with tungstenoxide, molybdenum oxide and/or vanadium oxide.

Hole-transport layer A′ preferably comprises a p-dopant selected fromorganic electron-acceptor compounds.

Particularly preferred embodiments of p-dopants are described below inconnection with p-dopants of hole-transport layer B.

The p-dopant in hole-transport layer A′ is preferably present in aconcentration of 0.1 to 20% by vol., preferably 0.5 to 12% by vol.,particularly preferably 1 to 8% by vol. and very particularly preferably2 to 6% by vol.

The hole-transport material matrix of hole-transport layer A′ can be anydesired organic material having hole-transporting properties.

The hole-transport material matrix for hole-transport layer A′ ispreferably indenofluorenamine derivatives (for example in accordancewith WO 06/122630 or WO 06/100896), the amine derivatives disclosed inEP 1661888, hexaazatriphenylene derivatives (for example in accordancewith WO 01/049806), amine derivatives containing condensed aromatic ringsystems (for example in accordance with U.S. Pat. No. 5,061,569), theamine derivatives disclosed in WO 95/09147, monobenzoindenofluorenamines(for example in accordance with WO 08/006449),dibenzoindenofluorenamines (for example in accordance with WO07/140847), spirobifluorenemonotriarylamines (for example in accordancewith WO 2012/034627 or the as yet unpublished EP 12000929.5),spirobifluorenetetrakistriarylamines, for example spiro-TAD orspiro-TTB, fluorenamines (for example in accordance with the as yetunpublished applications EP 12005369.9, EP 12005370.7 and EP12005371.5), spirodibenzopyranamines (for example in accordance with WO2013/083216) and dihydroacridine derivatives (for example in accordancewith WO 2012/150001).

The hole-transport material matrix is preferably selected fromtriarylamine compounds, preferably monotriarylamine compounds,particularly preferably from monotriarylamine compounds from thestructure classes mentioned above.

Alternatively, it may also be preferred for the hole-transport materialmatrix to be selected from bistriarylamine compounds or polytriarylaminecompounds, for example tetrakistriarylamine compounds.

A triarylamine compound is taken to mean a compound which contains oneor more triarylamine groups. A monotriarylamine compound is taken tomean a compound which contains a single triarylamine group. Atriarylamine group is a group in which three aryl or heteroaryl groupsare bonded to a common nitrogen atom. A monotriarylamine compoundpreferably contains no further arylamino group. A monotriarylaminecompound particularly preferably contains no further amino group.Analogously, bistriarylamine compounds and tetrakistriarylaminecompounds area defined as compounds which contain two or fourtriarylamine groups respectively.

Hole-transport layer A is preferably in direct contact with the anode orhole-transport layer N.

Hole-transport layer A preferably has a thickness of 100 to 300 nm,particularly preferably 130 to 230 nm.

Preferred hole-transport materials which are present in hole-transportlayer A are indenofluorenamine derivatives (for example in accordancewith WO 06/122630 or WO 06/100896), the amine derivatives disclosed inEP 1661888, hexaazatriphenylene derivatives (for example in accordancewith WO 01/049806), amine derivatives containing condensed aromatic ringsystems (for example in accordance with U.S. Pat. No. 5,061,569), theamine derivatives disclosed in WO 95/09147, monobenzoindenofluorenamines(for example in accordance with WO 08/006449),dibenzoindenofluorenamines (for example in accordance with WO07/140847), spirobifluorenemonotriarylamines (for example in accordancewith WO 2012/034627 or the as yet unpublished EP 12000929.5),spirobifluorenetetrakistriarylamines, for example spiro-TAD orspiro-TTB, fluorenamines (for example in accordance with the as yetunpublished applications EP 12005369.9, EP 12005370.7 and EP12005371.5), spirodibenzopyranamines (for example in accordance with WO2013/083216) and dihydroacridine derivatives (for example in accordancewith WO 2012/150001).

The hole-transport material is preferably selected from triarylaminecompounds, preferably monotriarylamine compounds, particularlypreferably from monotriarylamine compounds from the structure classesmentioned above.

Alternatively, it may also be preferred for the hole-transport materialto be selected from bistriarylamine compounds or polytriarylaminecompounds, for example tetrakistriarylamine compounds.

According to a preferred embodiment, hole-transport layer A comprisesthe same compound as hole-transport material as hole-transport layer A′does as hole-transport material matrix.

Hole-transport layer A furthermore preferably comprises no p-dopant. Itparticularly preferably comprises a single compound, i.e. is not a mixedlayer.

Hole-transport layer B is p-doped in accordance with the invention.

According to a preferred embodiment, hole-transport layer B is in directcontact with hole-transport layer A.

Preferred hole-transport material matrices of hole-transport layer Bbelong to the same structure classes as described above forhole-transport layer A. In particular, these are indenofluorenaminederivatives (for example in accordance with WO 06/122630 or WO06/100896), the amine derivatives disclosed in EP 1661888,hexaazatriphenylene derivatives (for example in accordance with WO01/049806), amine derivatives containing condensed aromatic ring systems(for example in accordance with U.S. Pat. No. 5,061,569), the aminederivatives disclosed in WO 95/09147, monobenzoindenofluorenamines (forexample in accordance with WO 08/006449), dibenzoindenofluorenamines(for example in accordance with WO 07/140847), spirobifluorenamines (forexample in accordance with WO 2012/034627 or the as yet unpublished EP12000929.5), spirobifluorenetetrakistriarylamines, for example spiro-TADor spiro-TTB, fluorenamines (for example in accordance with the as yetunpublished applications EP 12005369.9, EP 12005370.7 and EP12005371.5), spirodibenzopyranamines (for example in accordance with WO2013/083216) and dihydroacridine derivatives (for example in accordancewith WO 2012/150001).

The hole-transport material of layer B is preferably selected fromtriarylamine compounds, preferably monotriarylamine compounds,particularly preferably from monotriarylamine compounds from thestructure classes mentioned above.

Particularly preferred embodiments of p-dopants, in particular for thep-doped hole-transport layers A′ and B, are the compounds disclosed inWO 2011/073149, EP 1968131, EP 2276085, EP 2213662, EP 1722602, EP2045848, DE 102007031220, U.S. Pat. No. 8,044,390, U.S. Pat. No.8,057,712, WO 2009/003455, WO 2010/094378, WO 2011/120709, US2010/0096600 and WO 2012/095143.

Particularly preferred p-dopants are quinodimethane compounds,azaindenofluorenediones, azaphenalenes, azatriphenylenes, I₂, metalhalides, preferably transition-metal halides, metal oxides, preferablymetal oxides containing at least one transition metal or a metal frommain group 3, and transition-metal complexes, preferably complexes ofCu, Co, Ni, Pd and Pt with ligands containing at least one oxygen atomas bonding site. Preference is furthermore given to transition-metaloxides as dopants, preferably oxides of rhenium, molybdenum andtungsten, particularly preferably Re₂O₇, MoO₃, WO₃ and ReO₃.

The p-dopants are preferably substantially uniformly distributed in thep-doped layers. This can be achieved, for example, by co-evaporation ofthe p-dopant and the hole-transport material matrix.

The p-dopants are particularly preferably the following compounds:

The p-dopant is preferably present in hole-transport layer B in aconcentration of 0.1 to 20% by vol., preferably 0.5 to 12% by vol.,particularly preferably 1 to 8% by vol. and very particularly preferably2 to 6% by vol.

Hole-transport layer B preferably has a thickness of 5 to 50 nm,particularly preferably 10 to 40 nm.

Hole-transport layer C preferably comprises no p-dopant. It particularlypreferably comprises a single compound, i.e. is not a mixed layer.

According to a preferred embodiment, hole-transport layer C is in directcontact with hole-transport layer B. It is furthermore preferably indirect contact with the emitting layer on the anode side.

Preferred hole-transport materials of hole-transport layer C belong tothe same structure classes as described above for hole-transport layerA. In particular, these are indenofluorenamine derivatives (for examplein accordance with WO 06/122630 or WO 06/100896), the amine derivativesdisclosed in EP 1661888, hexaazatriphenylene derivatives (for example inaccordance with WO 01/049806), amine derivatives containing condensedaromatic ring systems (for example in accordance with U.S. Pat. No.5,061,569), the amine derivatives disclosed in WO 95/09147,monobenzoindenofluorenamines (for example in accordance with WO08/006449), dibenzoindenofluorenamines (for example in accordance withWO 07/140847), spirobifluorenamines (for (for example in accordance withWO 2012/034627 or the as yet unpublished EP 12000929.5),spirobifluorenetetrakistriarylamines, for example spiro-TAD orspiro-TTB, fluorenamines (for example in accordance with the as yetunpublished applications EP 12005369.9, EP 12005370.7 and EP12005371.5), spirodibenzopyranamines (for example in accordance with WO2013/083216) and dihydroacridine derivatives (for example in accordancewith WO 2012/150001).

The hole-transport material of layer C is preferably selected fromtriarylamine compounds, preferably monotriarylamine compounds,particularly preferably from monotriarylamine compounds from thestructure classes mentioned above.

Hole-transport layer C preferably has a thickness of 5 to 50 nm,particularly preferably 10 to 40 nm.

According to a preferred embodiment, the hole-transport materials ofhole-transport layers A and C are different.

It is preferred for the HOMO of the hole-transport material ofhole-transport layer C to be between −4.9 and −5.6 eV, preferablybetween −5.0 and −5.5 eV, and particularly preferably between −5.1 and−5.4 eV.

It is preferred for the HOMO of the hole-transport material ofhole-transport layer A to be higher than the HOMO of the hole-transportmaterial of hole-transport layer C by an amount of at least 0.2 eV,preferably at least 0.3 eV, particularly preferably at least 0.4 eV.

The value for the HOMO of the hole-transport material of hole-transportlayer A is preferably between −4.7 and −5.4 eV, preferably between −4.8and −5.3 eV, and particularly preferably between −4.9 eV and −5.2 eV.

The HOMO (highest occupied molecular orbital) is determined here byquantum-chemical calculations and calibrated with reference to cyclicvoltammetry measurements, as explained in greater detail in the workingexamples.

According to a further preferred embodiment, hole-transport layer Bcomprises the same compound as hole-transport material matrix ashole-transport layer C does as hole-transport material.

In a further preferred embodiment, hole-transport layer A comprises abistriarylamine compound or polytriarylamine compound, for example atetrakistriarylamine compound, and hole-transport layer C comprises amonotriarylamine compound. Hole-transport layer A particularlypreferably comprises a bistriarylamine compound or polytriarylaminecompound, for example a tetrakistriarylamine compound, andhole-transport layers B and C comprise a monotriarylamine compound.

It is preferred in accordance with the invention for hole-transportlayers A, B and C and, if present, hole-transport layer A′ to bedirectly adjacent to one another. In addition, it is preferred for theemitting layer or one of the emitting layers to be directly adjacent tohole-transport layer C.

It is preferred for hole-transport layers A, B, C and, if present, A′each to comprise one or more identical or different triarylaminecompounds.

They preferably each comprise one or more identical or differentmonotriarylamine compounds.

It is furthermore preferred for at least one of hole-transport layers A,B, C and A′ to comprise at least one compound of one of the formulae

where:

-   Z is on each occurrence, identically or differently, N or CR¹, where    Z is equal to C if a substituent is bonded;-   X, Y are on each occurrence, identically or differently, a single    bond, O, S, Se, BR¹, C(R¹)₂, Si(R¹)₂, NR¹, PR¹, C(R¹)₂—C(R¹)₂ or    CR¹═CR¹;-   E is O, S, Se, BR¹, C(R¹)₂, Si(R¹)₂, NR¹, PR¹, C(R¹)₂—C(R¹)₂ or    CR¹═CR¹;-   Ar¹ is on each occurrence, identically or differently, an aromatic    or heteroaromatic ring system having 5 to 60 aromatic ring atoms,    which may be substituted by one or more radicals R¹; and-   R¹ is on each occurrence, identically or differently, H, D, F, Cl,    Br, I, CHO, C(═O)R², P(═O)(R²)₂, S(═O)R², S(═O)₂R², CR²═CR²R², CN,    NO₂, Si(R²)₃, OSO₂R², a straight-chain alkyl, alkoxy or thioalkoxy    group having 1 to 40 C atoms or a straight-chain alkenyl or alkynyl    group having 2 to 40 C atoms or a branched or cyclic alkyl, alkenyl,    alkynyl, alkoxy or thioalkoxy group having 3 to 40 C atoms, each of    which may be substituted by one or more radicals R², where one or    more non-adjacent CH₂ groups may be replaced by R²C═CR², C≡C,    Si(R²)₂, Ge(R²)₂, Sn(R²)₂, C═O, C═S, C═Se, C═NR², P(═O)(R²), SO,    SO₂, NR², O, S or CONR² and where one or more H atoms may be    replaced by D, F, Cl, Br, I, CN or NO₂, or an aromatic or    heteroaromatic ring system having 5 to 60 aromatic ring atoms, which    may in each case be substituted by one or more radicals R², or a    combination of these systems; two or more adjacent substituents R¹    here may also form a mono- or polycyclic, aliphatic or aromatic ring    system with one another;-   R² is on each occurrence, identically or differently, H, D, CN or an    aliphatic, aromatic and/or heteroaromatic hydrocarbon radical having    1 to 20 C atoms, in which, in addition, H atoms may be replaced by D    or F; two or more adjacent substituents R² here may also form a    mono- or polycyclic, aliphatic or aromatic ring system with one    another;-   i is on each occurrence, identically or differently, 0 or 1, where    the sum of all i is at least equal to 1;-   p is equal to 0 or 1;-   m, n are, identically or differently, 0 or 1, where the sum of m and    n is equal to 1 or 2.

At least two of hole-transport layers A, B, C and A′ preferably compriseat least one compound of one of the formulae (I) to (VI), particularlypreferably at least three of hole-transport layers A, B, C and A′, andvery particularly preferably all of hole-transport layers A, B, C andA′.

In hole-transport layer A, compounds of the formulae (I), (II), (III)and (V) are preferably employed.

For the above-mentioned formulae (I) to (VI), it is preferred for notmore than three groups Z in a ring to be equal to N. It is generallypreferred for Z to be equal to CR¹.

The group X is preferably selected on each occurrence, identically ordifferently, from a single bond, C(R¹)₂, O and S and is particularlypreferably a single bond.

The group Y is preferably selected from O and C(R¹)₂ and is particularlypreferably O.

The group E is preferably selected from C(R¹)₂, O and S and isparticularly preferably C(R¹)₂.

The group Ar¹ is selected on each occurrence, identically ordifferently, from aromatic or heteroaromatic ring systems having 6 to 30aromatic ring atoms, which may be substituted by one or more radicalsR¹. Ar¹ is particularly preferably selected from aryl or heteroarylgroups having 6 to 18 aromatic ring atoms, which may be substituted byone or more radicals R¹.

R¹ is selected on each occurrence, identically or differently, from H,D, F, Cl, Br, I, C(═O)R², CN, Si(R²)₃, N(R²)₂, NO₂, P(═O)(R²)₂, S(═O)R²,S(═O)₂R², a straight-chain alkyl, alkoxy or thioalkyl group having 1 to20 C atoms or a branched or cyclic alkyl, alkoxy or thioalkyl grouphaving 3 to 20 C atoms or an alkenyl or alkynyl group having 2 to 20 Catoms, where the above-mentioned groups may each be substituted by oneor more radicals R² and where one or more CH₂ groups in theabove-mentioned groups may be replaced by —R²C═CR²—, Si(R²)₂, C═O, C═S,C═NR², —C(═O)O—, —C(═O)NR²—, NR², P(═O)(R²), —O—, —S—, SO or SO₂ andwhere one or more H atoms in the above-mentioned groups may be replacedby D, F, Cl, Br, I, CN or NO₂, or an aromatic or heteroaromatic ringsystem having 5 to 30 aromatic ring atoms, which may in each case besubstituted by one or more radicals R², where two or more radicals R¹may be linked to one another and may form a ring.

The following definitions apply in general:

An aryl group in the sense of this invention contains 6 to 60 aromaticring atoms; a heteroaryl group in the sense of this invention contains 5to 60 aromatic ring atoms, at least one of which is a heteroatom. Theheteroatoms are preferably selected from N, O and S. This represents thebasic definition. If other preferences are indicated in the descriptionof the present invention, for example with respect to the number ofaromatic ring atoms or the heteroatoms present, these apply.

An aryl group or heteroaryl group here is taken to mean either a simplearomatic ring, i.e. benzene, or a simple heteroaromatic ring, forexample pyridine, pyrimidine or thiophene, or a condensed (annellated)aromatic or heteroaromatic polycycle, for example naphthalene,phenanthrene, quinoline or carbazole. A condensed (annellated) aromaticor heteroaromatic polycycle in the sense of the present applicationconsists of two or more simple aromatic or heteroaromatic ringscondensed with one another.

An aryl or heteroaryl group, which may in each case be substituted bythe above-mentioned radicals and which may be linked to the aromatic orheteroaromatic ring system via any desired positions, is taken to mean,in particular, groups derived from benzene, naphthalene, anthracene,phenanthrene, pyrene, dihydropyrene, chrysene, perylene, fluoranthene,benzanthracene, benzophenanthrene, tetracene, pentacene, benzopyrene,furan, benzofuran, isobenzofuran, dibenzofuran, thiophene,benzothiophene, isobenzothiophene, dibenzothiophene, pyrrole, indole,isoindole, carbazole, pyridine, quinoline, isoquinoline, acridine,phenanthridine, benzo-5,6-quinoline, benzo-6,7-quinoline,benzo-7,8-quinoline, phenothiazine, phenoxazine, pyrazole, indazole,imidazole, benzimidazole, naphthimidazole, phenanthrimidazole,pyridimidazole, pyrazinimidazole, quinoxalinimidazole, oxazole,benzoxazole, naphthoxazole, anthroxazole, phenanthroxazole, isoxazole,1,2-thiazole, 1,3-thiazole, benzothiazole, pyridazine, benzopyridazine,pyrimidine, benzopyrimidine, quinoxaline, pyrazine, phenazine,naphthyridine, azacarbazole, benzocarboline, phenanthroline,1,2,3-triazole, 1,2,4-triazole, benzotriazole, 1,2,3-oxadiazole,1,2,4-oxadiazole, 1,2,5-oxadiazole, 1,3,4-oxadiazole, 1,2,3-thiadiazole,1,2,4-thiadiazole, 1,2,5-thiadiazole, 1,3,4-thiadiazole, 1,3,5-triazine,1,2,4-triazine, 1,2,3-triazine, tetrazole, 1,2,4,5-tetrazine,1,2,3,4-tetrazine, 1,2,3,5-tetrazine, purine, pteridine, indolizine andbenzothiadiazole.

An aromatic ring system in the sense of this invention contains 6 to 60C atoms in the ring system. A heteroaromatic ring system in the sense ofthis invention contains 5 to 60 aromatic ring atoms, at least one ofwhich is a heteroatom. The heteroatoms are preferably selected from N, Oand/or S. An aromatic or heteroaromatic ring system in the sense of thisinvention is intended to be taken to mean a system which does notnecessarily contain only aryl or heteroaryl groups, but instead inwhich, in addition, a plurality of aryl or heteroaryl groups may beconnected by a non-aromatic unit (preferably less than 10% of the atomsother than H), such as, for example, an sp³-hybridised C, Si, N or Oatom, an sp²-hybridised C or N atom or an sp-hybridised C atom. Thus,for example, systems such as 9,9′-spirobifluorene, 9,9′-diarylfluorene,triarylamine, diaryl ether, stilbene, etc., are also intended to betaken to be aromatic ring systems in the sense of this invention, as aresystems in which two or more aryl groups are connected, for example, bya linear or cyclic alkyl, alkenyl or alkynyl group or by a silyl group.Furthermore, systems in which two or more aryl or heteroaryl groups arelinked to one another via single bonds are also taken to be aromatic orheteroaromatic ring systems in the sense of this invention, such as, forexample, systems such as biphenyl, terphenyl or diphenyltriazine.

An aromatic or heteroaromatic ring system having 5-60 aromatic ringatoms, which may in each case also be substituted by radicals as definedabove and which may be linked to the aromatic or heteroaromatic groupvia any desired positions, is taken to mean, in particular, groupsderived from benzene, naphthalene, anthracene, benzanthracene,phenanthrene, benzophenanthrene, pyrene, chrysene, perylene,fluoranthene, naphthacene, pentacene, benzopyrene, biphenyl,biphenylene, terphenyl, terphenylene, quaterphenyl, fluorene,spirobifluorene, dihydrophenanthrene, dihydropyrene, tetrahydropyrene,cis- or trans-indenofluorene, truxene, isotruxene, spirotruxene,spiroisotruxene, furan, benzofuran, isobenzofuran, dibenzofuran,thiophene, benzothiophene, isobenzothiophene, dibenzothiophene, pyrrole,indole, isoindole, carbazole, indolocarbazole, indenocarbazole,pyridine, quinoline, isoquinoline, acridine, phenanthridine,benzo-5,6-quinoline, benzo-6,7-quinoline, benzo-7,8-quinoline,phenothiazine, phenoxazine, pyrazole, indazole, imidazole,benzimidazole, naphthimidazole, phenanthrimidazole, pyridimidazole,pyrazinimidazole, quinoxalinimidazole, oxazole, benzoxazole,naphthoxazole, anthroxazole, phenanthroxazole, isoxazole, 1,2-thiazole,1,3-thiazole, benzothiazole, pyridazine, benzopyridazine, pyrimidine,benzopyrimidine, quinoxaline, 1,5-diazaanthracene, 2,7-diazapyrene,2,3-diazapyrene, 1,6-diazapyrene, 1,8-diazapyrene, 4,5-diazapyrene,4,5,9,10-tetraazaperylene, pyrazine, phenazine, phenoxazine,phenothiazine, fluorubin, naphthyridine, azacarbazole, benzocarboline,phenanthroline, 1,2,3-triazole, 1,2,4-triazole, benzotriazole,1,2,3-oxadiazole, 1,2,4-oxadiazole, 1,2,5-oxadiazole, 1,3,4-oxadiazole,1,2,3-thiadiazole, 1,2,4-thiadiazole, 1,2,5-thiadiazole,1,3,4-thiadiazole, 1,3,5-triazine, 1,2,4-triazine, 1,2,3-triazine,tetrazole, 1,2,4,5-tetrazine, 1,2,3,4-tetrazine, 1,2,3,5-tetrazine,purine, pteridine, indolizine and benzothiadiazole, or combinations ofthese groups.

For the purposes of the present invention, a straight-chain alkyl grouphaving 1 to 40 C atoms or a branched or cyclic alkyl group having 3 to40 C atoms or an alkenyl or alkynyl group having 2 to 40 C atoms, inwhich, in addition, individual H atoms or CH₂ groups may be substitutedby the groups mentioned above under the definition of the radicals, ispreferably taken to mean the radicals methyl, ethyl, n-propyl, i-propyl,n-butyl, i-butyl, s-butyl, t-butyl, 2-methylbutyl, n-pentyl, s-pentyl,cyclopentyl, neopentyl, n-hexyl, cyclohexyl, neohexyl, n-heptyl,cycloheptyl, n-octyl, cyclooctyl, 2-ethylhexyl, trifluoromethyl,pentafluoroethyl, 2,2,2-trifluoroethyl, ethenyl, propenyl, butenyl,pentenyl, cyclopentenyl, hexenyl, cyclohexenyl, heptenyl, cycloheptenyl,octenyl, cyclooctenyl, ethynyl, propynyl, butynyl, pentynyl, hexynyl oroctynyl. An alkoxy or thioalkyl group having 1 to 40 C atoms ispreferably taken to mean methoxy, trifluoromethoxy, ethoxy, n-propoxy,i-propoxy, n-butoxy, i-butoxy, s-butoxy, t-butoxy, n-pentoxy, s-pentoxy,2-methylbutoxy, n-hexoxy, cyclohexyloxy, n-heptoxy, cycloheptyloxy,n-octyloxy, cyclooctyloxy, 2-ethylhexyloxy, pentafluoroethoxy,2,2,2-trifluoroethoxy, methylthio, ethylthio, n-propylthio,i-propylthio, n-butylthio, i-butylthio, s-butylthio, t-butylthio,n-pentylthio, s-pentylthio, n-hexylthio, cyclohexylthio, n-heptylthio,cycloheptylthio, n-octylthio, cyclooctylthio, 2-ethylhexylthio,trifluoromethylthio, pentafluoroethylthio, 2,2,2-trifluoroethylthio,ethenylthio, propenylthio, butenylthio, pentenylthio, cyclopentenylthio,hexenylthio, cyclohexenylthio, heptenylthio, cycloheptenylthio,octenylthio, cyclooctenylthio, ethynylthio, propynylthio, butynylthio,pentynylthio, hexynylthio, heptynylthio or octynylthio.

The formulation that two or more radicals are able to form a ring withone another is intended for the purposes of the present application tobe taken to mean, inter alia, that the two radicals are linked to oneanother by a chemical bond. Furthermore, however, the above-mentionedformulation is also intended to be taken to mean that, in the case whereone of the two radicals is hydrogen, the second radical is bonded to theposition to which the hydrogen atom was bonded, with formation of aring.

Examples of preferred hole-transport materials for use in the electronicdevice in accordance with the present invention, in particular in layersA′, A, B and C, are shown below.

The electronic device according to the invention can comprise one ormore emitting layers. The emitting layers can be fluorescent orphosphorescent, i.e. comprise fluorescent or phosphorescent emitters.

The term phosphorescent emitters (dopants) typically encompassescompounds in which the light emission takes place through aspin-forbidden transition, for example a transition from an excitedtriplet state or a state having a relatively high spin quantum number,for example a quintet state.

Suitable phosphorescent emitters are, in particular, compounds whichemit light, preferably in the visible region, on suitable excitation andin addition contain at least one atom having an atomic number greaterthan 20, preferably greater than 38 and less than 84, particularlypreferably greater than 56 and less than 80. The phosphorescent dopantsused are preferably compounds which contain copper, molybdenum,tungsten, rhenium, ruthenium, osmium, rhodium, iridium, palladium,platinum, silver, gold or europium, in particular compounds whichcontain iridium, platinum or copper.

For the purposes of the present invention, all luminescent iridium,platinum or copper complexes are regarded as phosphorescent compounds.

Examples of the phosphorescent dopants described above are revealed bythe applications WO 2000/70655, WO 2001/41512, WO 2002/02714, WO2002/15645, EP 1191613, EP 1191612, EP 1191614, WO 2005/033244, WO2005/019373 and US 2005/0258742. In general, all phosphorescentcomplexes as used in accordance with the prior art for phosphorescentOLEDs and as are known to the person skilled in the art in the area oforganic electroluminescent devices are suitable for use in the devicesaccording to the invention. The person skilled in the art will also beable to employ further phosphorescent complexes without inventive stepin combination with the compounds according to the invention in OLEDs.

Preferred fluorescent emitters for use in the electronic devicesaccording to the invention are selected from the class of thetriarylamine compounds, as defined above. At least one of the aryl orheteroaryl groups bonded to the nitrogen atom is preferably a condensedring system, particularly preferably having at least 14 aromatic ringatoms. Preferred examples thereof are aromatic anthracenamines, aromaticanthracenediamines, aromatic pyrenamines, aromatic pyrenediamines,aromatic chrysenamines or aromatic chrysenediamines. An aromaticanthracenamine is taken to mean a compound in which one diarylaminogroup is bonded directly to an anthracene group, preferably in the9-position. An aromatic anthracenediamine is taken to mean a compound inwhich two diarylamino groups are bonded directly to an anthracene group,preferably in the 9,10-position. Aromatic pyrenamines, pyrenediamines,chrysenamines and chrysenediamines are defined analogously thereto,where the diarylamino groups are preferably bonded to the pyrene in the1-position or in the 1,6-position. Further preferred dopants areindenofluorenamines and indenofluorenediamines, for example inaccordance with WO 2006/108497 or WO 2006/122630,benzoindenofluorenamines and benzoindenofluorenediamines, for example inaccordance with WO 2008/006449, and dibenzoindenofluorenamines anddibenzoindenofluorenediamines, for example in accordance with WO2007/140847, as well as the indenofluorene derivatives containingcondensed aryl groups disclosed in WO 2010/012328. Preference islikewise given to the pyrenearylamines disclosed in WO 2012/048780 andthe as yet unpublished EP 12004426.8. Preference is likewise given tothe benzoindenofluorenamines disclosed in the as yet unpublished EP12006239.3 and the benzofluorenamines disclosed in the as yetunpublished EP 13000012.8.

The emitting layer preferably comprises one or more host materials(matrix materials) and one or more dopant materials (emitter materials).

According to a preferred embodiment, an emitting layer comprises aplurality of matrix materials (mixed-matrix systems) and/or a pluralityof dopants. In this case too, the dopants are generally the materialswhose proportion in the system is the smaller and the matrix materialsare the materials whose proportion in the system is the greater. Inindividual cases, however, the proportion of an individual matrixmaterial in the system may be smaller than the proportion of anindividual dopant.

In mixed-matrix systems, one of the two matrix materials is preferably amaterial having hole-transporting properties and the other material is amaterial having electron-transporting properties. The desiredelectron-transporting and hole-transporting properties of themixed-matrix components may, however, also be mainly or completelycombined in a single mixed-matrix component, where the furthermixed-matrix component or mixed-matrix components fulfil(s) otherfunctions. The two different matrix materials may be present here in aratio of 1:50 to 1:1, preferably 1:20 to 1:1, particularly preferably1:10 to 1:1 and very particularly preferably 1:4 to 1:1. Preference isgiven to the use of mixed-matrix systems in phosphorescent organicelectroluminescent devices. Preferred embodiments of mixed-matrixsystems are disclosed, inter alia, in the application WO 2010/108579.

The mixed-matrix systems may include one or more dopants, preferably oneor more phosphorescent dopants. In general, mixed-matrix systems arepreferably employed in phosphorescent emitting layers.

Preferred matrix materials for fluorescent emitters are selected fromthe classes of the oligoarylenes (for example2,2′,7,7′-tetraphenylspirobifluorene in accordance with EP 676461 ordinaphthylanthracene), in particular the oligoarylenes containingcondensed aromatic groups, the oligoarylenevinylenes (for example DPVBior spiro-DPVBi in accordance with EP 676461), the polypodal metalcomplexes (for example in accordance with WO 2004/081017), thehole-conducting compounds (for example in accordance with WO2004/058911), the electron-conducting compounds, in particular ketones,phosphine oxides, sulfoxides, etc. (for example in accordance with WO2005/084081 and WO 2005/084082), the atropisomers (for example inaccordance with WO 2006/048268), the boronic acid derivatives (forexample in accordance with WO 2006/117052) or the benzanthracenes (forexample in accordance with WO 2008/145239). Particularly preferredmatrix materials are selected from the classes of the oligoarylenes,comprising naphthalene, anthracene, benzanthracene and/or pyrene oratropisomers of these compounds, the oligoarylenevinylenes, the ketones,the phosphine oxides and the sulfoxides. Very particularly preferredmatrix materials are selected from the classes of the oligoarylenes,comprising anthracene, benzanthracene, benzophenanthrene and/or pyreneor atropisomers of these compounds. An oligoarylene in the sense of thisinvention is intended to be taken to mean a compound in which at leastthree aryl or arylene groups are bonded to one another.

Preferred matrix materials for phosphorescent emitters are aromaticketones, aromatic phosphine oxides or aromatic sulfoxides or sulfones,for example in accordance with WO 2004/013080, WO 2004/093207, WO2006/005627 or WO 2010/006680, triaryiamines, carbazole derivatives, forexample CBP (N,N-biscarbazolylbiphenyl) or the carbazole derivativesdisclosed in WO 2005/039246, US 2005/0069729, JP 2004/288381, EP 1205527or WO 2008/086851, indolocarbazole derivatives, for example inaccordance with WO 2007/063754 or WO 2008/056746, indenocarbazolederivatives, for example in accordance with WO 2010/136109, WO2011/000455 or WO 2013/041176, azacarbazole derivatives, for example inaccordance with EP 1617710, EP 1617711, EP 1731584, JP 2005/347160,bipolar matrix materials, for example in accordance with WO 2007/137725,silanes, for example in accordance with WO 2005/111172, azaboroles orboronic esters, for example in accordance with WO 2006/117052, triazinederivatives, for example in accordance with WO 2010/015306, WO2007/063754 or WO 2008/056746, zinc complexes, for example in accordancewith EP 652273 or WO 2009/062578, diazasilole or tetraazasilolederivatives, for example in accordance with WO 2010/054729,diazaphosphole derivatives, for example in accordance with WO2010/054730, bridged carbazole derivatives, for example in accordancewith US 2009/0136779, WO 2010/050778, WO 2011/042107, WO 2011/088877 orWO 2012/143080, triphenylene derivatives, for example in accordance withWO 2012/048781, or lactams, for example in accordance with WO2011/116865 or WO 2011/137951.

The electronic device according to the invention may comprise aplurality of emitting layers. These emission layers in this caseparticularly preferably have in total a plurality of emission maximabetween 380 nm and 750 nm, resulting overall in white emission, i.e.various emitting compounds which are able to fluoresce or phosphoresceand which emit blue or yellow or orange or red light are used in theemitting layers. Particular preference is given to three-layer systems,i.e. systems having three emitting layers, where at least one of theselayers preferably comprises at least one compound of the formula (I) andwhere the three layers exhibit blue, green and orange or red emission(for the basic structure see, for example, WO 2005/011013).Alternatively and/or additionally, the compounds according to theinvention may also be present in the hole-transport layer or in anotherlayer. It should be noted that, for the generation of white light, anemitter compound used individually which emits in a broad wavelengthrange may also be suitable instead of a plurality of emitter compoundswhich emit in colours.

The cathode of the electronic device according to the inventionpreferably comprises metals having a low work function, metal alloys ormultilayered structures comprising various metals, such as, for example,alkaline-earth metals, alkali metals, main-group metals or lanthanoids(for example Ca, Ba, Mg, Al, In, Mg, Yb, Sm, etc.). Also suitable arealloys comprising an alkali metal or alkaline-earth metal and silver,for example an alloy comprising magnesium and silver. In the case ofmultilayered structures, further metals which have a relatively highwork function, such as, for example, Ag or Al, can also be used inaddition to the said metals, in which case combinations of the metals,such as, for example, Ca/Ag, Mg/Ag or Ba/Ag, are generally used. It mayalso be preferred to introduce a thin interlayer of a material having ahigh dielectric constant between a metallic cathode and the organicsemiconductor. Suitable for this purpose are, for example, alkali metalfluorides or alkaline-earth metal fluorides, but also the correspondingoxides or carbonates (for example LiF, Li₂O, BaF₂, MgO, NaF, CsF,Cs₂CO₃, etc.). Furthermore, lithium quinolinate (LiQ) can be used forthis purpose. The layer thickness of this layer is preferably between0.5 and 5 nm.

Besides anode, cathode, emitting layer and hole-transport layers A, B, Cand optionally hole-transport layer A′, the electronic device accordingto the invention preferably also comprises further functional layers.

The sequence of the layers of the electronic device is preferably thefollowing: anode/hole-transport layer A′/hole-transport layerA/hole-transport layer B/hole-transport layer C/emittinglayer/electron-transport layer/electron-injection layer/cathode.

All of the said layers do not have to be present, and/or further layersmay be present in addition to the said layers.

These additional layers are preferably selected from hole-injectionlayers, hole-transport layers, electron-blocking layers, emittinglayers, interlayers, electron-transport layers, electron-injectionlayers, hole-blocking layers, exciton-blocking layers, charge-generationlayers, p/n junctions and coupling-out layers.

The electronic device according to the invention preferably has at leastone electron-transport layer, which is arranged between emitting layerand cathode, where the electron-transport layer preferably comprises atleast one n-dopant and at least one electron-transport material matrix.

An n-dopant is taken to mean a compound which is able to at leastpartially reduce the other compound present in the layer (the matrix)and in this way increases the conductivity of the layer. n-Dopants inaccordance with the present application are typically electron-donorcompounds or strong reducing agents. n-Dopants which can be used are,for example, the materials disclosed in Chem. Rev, 2007, 107, pp. 1233ff., Section 2.2, such as alkali metals, alkaline-earth metals andelectron-rich and readily oxidisable organic compounds ortransition-metal complexes.

Furthermore, the electronic device according to the invention preferablyhas at least one electron-injection layer, which is arranged betweenelectron-transport layer and cathode. The electron-injection layer ispreferably directly adjacent to the cathode.

The materials used for the electron-transport layer andelectron-injection layer can be all materials as are used in accordancewith the prior art as electron-transport materials in theelectron-transport layer. In particular, aluminium complexes, forexample Alq₃, zirconium complexes, for example Zrq₄, benzimidazolederivatives, triazine derivatives, pyrimidine derivatives, pyridinederivatives, pyrazine derivatives, quinoxaline derivatives, quinolinederivatives, oxadiazole derivatives, aromatic ketones, lactams, boranes,diazaphosphole derivatives and phosphine oxide derivatives are suitable.Furthermore suitable materials are derivatives of the above-mentionedcompounds, as disclosed in JP 2000/053957, WO 2003/060956, WO2004/028217, WO 2004/080975 and WO 2010/072300.

During production, the device is preferably structured, provided withcontacts and finally sealed in order to exclude water and/or air.

In a preferred embodiment, the electronic device according to theinvention is characterised in that one or more layers are coated bymeans of a sublimation process, in which the materials are applied byvapour deposition in vacuum sublimation units at an initial pressure ofless than 10⁻⁵ mbar, preferably less than 10⁻⁶ mbar. However, it is alsopossible here for the initial pressure to be even lower, for exampleless than 10⁻⁷ mbar.

It is likewise preferred for one or more layers in the electronic deviceaccording to the invention to be coated by means of the OVPD (organicvapour phase deposition) process or with the aid of carrier-gassublimation, in which the materials are applied at a pressure of between10⁻⁵ mbar and 1 bar. A special case of this process is the OVJP (organicvapour jet printing) process, in which the materials are applieddirectly through a nozzle and are thus structured (for example M. S.Arnold et al., Appl. Phys. Lett. 2008, 92, 053301).

It is likewise preferred for one or more layers in the electronic deviceaccording to the invention to be produced from solution, such as, forexample, by spin coating, or by means of any desired printing process,such as, for example, screen printing, flexographic printing, nozzleprinting or offset printing, but particularly preferably LITI (lightinduced thermal imaging, thermal transfer printing) or ink-jet printing.

It is furthermore preferred, for the production of the electronic deviceaccording to the invention, to apply one or more layers from solutionand one or more layers by a sublimation process.

The electronic devices according to the invention can be employed indisplays, as light sources in lighting applications and as light sourcesin medical and/or cosmetic applications (for example phototherapy).

WORKING EXAMPLES

Part A: Determination of the HOMO Positions of Compounds

The HOMO positions of the materials are determined via quantum-chemicalcalculations. To this end, use is made of the “Gaussian03W” softwarepackage (Gaussian Inc.). In order to calculate organic substanceswithout metals, firstly a geometry optimisation is carried out using the“Ground State/Semi-empirical/Default Spin/AM1/Charge 0/Spin Singlet”method. An energy calculation is subsequently carried out on the basisof the optimised geometry. The “TD-SFC/DFT/Default Spin/B3PW91” methodwith the “6-31G(d)” base set is used here (Charge 0, Spin Singlet). Theenergy calculation gives the HOMO HEh in hartree units. The HOMO valuesin electron-volts calibrated with reference to cyclic voltammetrymeasurements are determined therefrom as follows:HOMO (eV)=((HEh*27.212)−0.9899)/1.1206

These values are to be regarded as the HOMO of the materials in thesense of this application.

Table with HOMO data for the compounds used (structures see below)

Material HOMO HIM1/HTM1 −5.25 eV HIM 2 −4.85 eV NPB −5.16 eV HTM2 −5.43eV HTM3 −5.23 eV HTM4 −5.35 eV HTM5 −5.32 eV HTM6 −5.23 eVPart B: Production of OLEDs

OLEDs according to the invention and OLEDs in accordance with the priorart are produced by a general process in accordance with WO 04/058911,which is adapted to the circumstances described here (layer-thicknessvariation, materials).

The data for various OLEDs are presented in the following Examples E1 toE13 according to the invention and in the reference Examples V1-V11. Thesubstrates used are glass plates coated with structured ITO (indium tinoxide) in a thickness of 50 nm. The OLEDs basically have the followinglayer structure: substrate/p-doped hole-transport layer A′(HIL1)/hole-transport layer A (HTL)/p-doped hole-transport layer B(HIL2)/hole-transport layer C (EBL)/emission layer(EML)/electron-transport layer (ETL)/electron-injection layer (EIL) andfinally a cathode. The cathode is formed by an aluminium layer with athickness of 100 nm. The materials required for the production of theOLEDs are shown in Table 1, the structure of the various electronicdevices produced is shown in Table 2.

All materials are applied by thermal vapour deposition in a vacuumchamber. The emission layer here always consists of at least one matrixmaterial (host material) and an emitting dopant (emitter), which isadmixed with the matrix material or matrix materials in a certainproportion by volume by co-evaporation. An expression such asH1:SEB1(5%) here means that material H1 is present in the layer in aproportion by volume of 95% and SEB1 is present in the layer in aproportion of 5%. Analogously, the electron-transport layer or thehole-injection layers may also consist of a mixture of two materials.

The OLEDs are characterised by standard methods. For this purpose, theelectroluminescence spectra, the current efficiency (measured in cd/A),the power efficiency (measured in lm/W) and the external quantumefficiency (EQE, measured in percent) as a function of the luminousdensity, calculated from current/voltage/luminous density characteristiclines (IUL characteristic lines) assuming Lambert emissioncharacteristics, and the lifetime are determined. Theelectroluminescence spectra are determined at a luminous density of 1000cd/m², and the CIE 1931 x and y colour coordinates are calculatedtherefrom. The expression EQE @ 10 mA/cm² denotes the external quantumefficiency at a current density of 10 mA/cm². LT80 @ 60 mA/cm² is thelifetime by which the ° LED has dropped to 80% of the initial intensityat an initial luminance at constant current of 60 mA/cm².

TABLE 1 Structures of the materials used

  F4TCNQ

  HIM1

  HIM2

  H1

  SEB1

  SEB2

  H2

  TEG

  ETM

  LiQ

  NPB

  HTM1

  HTM2

  HTM3

  HTM4

  HTM5

  HTM6

  HAT-CN

TABLE 2 Structure of the OLEDs HIL1 HTL HIL2 EBL EML ETL EIL Thickness/Thickness/ Thickness/ Thickness/ Thickness/ Thickness/ Thickness/ Ex. nmnm nm nm nm nm nm V1 HIM1:F4TCNQ (3%) HIM1 HTM1 H1:SEB1 (5%) ETM(50%):LiQ (50%) LiQ 20 nm 175 nm 20 nm 20 nm 30 nm 1 nm E1 HIM1:F4TCNQ(3%) HIM1 HTM1:F4TCNQ (3%) HTM1 H1:SEB1 (5%) ETM (50%):LiQ (50%) LiQ 20nm 155 nm 20 nm 20 nm 20 nm 30 nm 1 nm V2 HIM1:F4TCNQ (3%) HIM1 HTM1H2:TEG (10%) ETM (50%):LiQ (50%) LiQ 20 nm 210 nm 20 nm 40 nm 30 nm 1 nmE2 HIM1:F4TCNQ (3%) HIM1 HTM1:F4TCNQ (3%) HTM1 H2:TEG (10%) ETM(50%):LiQ (50%) LiQ 20 nm 190 nm 20 nm 20 nm 40 nm 30 nm 1 nm V3HIM1:F4TCNQ (3%) HIM1 HTM2 H1:SEB1 (5%) ETM (50%):LiQ (50%) LiQ 20 nm175 nm 20 nm 20 nm 30 nm 1 nm E3 HIM1:F4TCNQ (3%) HIM1 HTM2:F4TCNQ (3%)HTM2 H1:SEB1 (5%) ETM (50%):LiQ (50%) LiQ 20 nm 155 nm 20 nm 20 nm 20 nm30 nm 1 nm E4 HIM1:F4TCNQ (3%) HIM1 HTM1:F4TCNQ (3%) HTM2 H1:SEB1 (5%)ETM (50%):LiQ (50%) LiQ 20 nm 155 nm 20 nm 20 nm 20 nm 30 nm 1 nm V4HIM1:F4TCNQ (3%) HIM1 HTM3 H1:SEB1 (5%) ETM (50%):LiQ (50%) LiQ 20 nm175 nm 20 nm 20 nm 30 nm 1 nm E5 HIM1:F4TCNQ (3%) HIM1 HTM3:F4TCNQ (3%)HTM3 H1:SEB1 (5%) ETM (50%):LiQ (50%) LiQ 20 nm 155 nm 20 nm 20 nm 20 nm30 nm 1 nm E6 HIM1:F4TCNQ (3%) HIM1 HTM1:F4TCNQ (3%) HTM3 H1:SEB1 (5%)ETM (50%):LiQ (50%) LiQ 20 nm 155 nm 20 nm 20 nm 20 nm 30 nm 1 nm V5HIM1:F4TCNQ (3%) HIM1 NPB H1:SEB1 (5%) ETM LiQ 20 nm 175 nm 20 nm 20 nm30 nm 3 nm E7 HIM1:F4TCNQ (3%) HIM1 NPB:F4TCNQ (3%) NPB H1:SEB1 (5%) ETMLiQ 20 nm 155 nm 20 nm 20 nm 20 nm 30 nm 3 nm V6 HIM2:F4TCNQ (3%) HIM2HTM1 H1:SEB2 (5%) ETM (50%):LiQ (50%) LiQ 10 nm 140 nm 30 nm 20 nm 30 nm1 nm V7 HIM2:F4TCNQ (3%) HTM1 H1:SEB2 (5%) ETM (50%):LiQ (50%) LiQ 150nm 30 nm 20 nm 30 nm 1 nm E8 HIM2:F4TCNQ (3%) HIM2 HTM1:F4TCNQ (3%) HTM1H1:SEB2 (5%) ETM (50%):LiQ (50%) LiQ 10 nm 140 nm 20 nm 10 nm 20 nm 30nm 1 nm V8 HIM1:F4TCNQ (3%) HIM1 HTM4 H1:SEB1 (5%) ETM (50%):LiQ (50%)LiQ 20 nm 160 nm 20 nm 20 nm 30 nm 1 nm E9 HIM1:F4TCNQ (3%) HIM1HTM5:F4TCNQ (3%) HTM4 H1:SEB1 (5%) ETM (50%):LiQ (50%) LiQ 20 nm 140 nm20 nm 20 nm 20 nm 30 nm 1 nm V9 HIM1:F4TCNQ (3%) HIM1 HTM5 H1:SEB1 (5%)ETM (50%):LiQ (50%) LiQ 20 nm 179 nm 20 nm 20 nm 30 nm 1 nm E10HIM1:F4TCNQ (3%) HIM1 HTM6:F4TCNQ (3%) HTM5 H1:SEB1 (5%) ETM (50%):LiQ(50%) LiQ 20 nm 155 nm 20 nm 20 nm 20 nm 30 nm 1 nm E11 HIM1:F4TCNQ (3%)HIM1 HTM1:F4TCNQ (3%) HTM5 H1:SEB1 (5%) ETM (50%):LiQ (50%) LiQ 20 nm155 nm 20 nm 20 nm 20 nm 30 nm 1 nm V10 HIM1:F4TCNQ (3%) HIM1 HTM6H1:SEB1 (5%) ETM (50%):LiQ (50%) LiQ 20 nm 175 nm 20 nm 20 nm 30 nm 1 nmE12 HIM1:F4TCNQ (3%) HIM1 HTM6:F4TCNQ (3%) HTM6 H1:SEB1 (5%) ETM(50%):LiQ (50%) LiQ 20 nm 155 nm 20 nm 20 nm 20 nm 30 nm 1 nm E13HIM1:F4TCNQ (3%) HIM1 HTM1:F4TCNQ (3%) HTM6 H1:SEB1 (5%) ETM (50%):LiQ(50%) LiQ 20 nm 155 nm 20 nm 20 nm 20 nm 30 nm 1 nm V11 HIM2:F4TCNQ (3%)HIM2 Hat-CN HTM1 H1:SEB2 (5%) ETM (50%):LiQ (50%) LiQ 10 nm 140 nm 10 nm20 nm 20 nm 30 nm 1 nm

Example 1

A reference sample V1 was prepared and compared with sample E1 accordingto the invention. HIM1 and HTM1 are the same material in this example.Reference sample V1 has a voltage of 4.0 V, an external quantumefficiency of 7.7% and a lifetime (LT80 @ 60 mA/cm²) of 105 h at acurrent density of 10 mA/cm². By comparison, both the external quantumefficiency at a current density of 10 mA/cm² is higher at 8.1% in thecase of sample E1 according to the invention, and also the lifetimemeasured (LT80 @ 60 mA/cm²) of 220 h is shorter at the same time as alower voltage of 3.9 V. The colour coordinates according to CIE 1931 are(0.14/0.14) for comparative sample V1 and (0.14/0.14) for sample E1according to the invention.

A further comparison is reference sample V2 with sample E2 according tothe invention. Here too, materials HIM1 and HTM1 are identical. Heretoo, sample E2 according to the invention has both a higher quantumefficiency (@ 2 mA/cm²) of 20.0% compared with reference sample V2 of19.9% and also a longer lifetime (LT80 @ 20 mA/cm²) of 165 h comparedwith reference sample E2 of 110 h. The voltage of the reference sample(@ 2 mA) was 3.3 V and was higher than the voltage of sample E2 of 3.1V. The CIE colour coordinates of the samples were (0.34/0.63).

Example 2

In this example, different materials are present in each ofhole-transport layers A and C.

Compared with reference sample V3, samples E3 and E4 according to theinvention exhibit a significantly longer lifetime (LT80 @ 60 mA/cm²) of305 h (E3) and 135 h (E4) compared with 45 h (V3). The quantumefficiency (@ 10 mA/cm²) of reference sample V3 is, at 8.9%, somewhathigher than that of sample E3, at 8.3%, and somewhat lower than that ofsample E4, at 9.8%. The voltage of the reference sample of 4.4 V at 10mA/cm² was higher than that of samples E3, at 4.1 V, and E4, at 4.2 V.

Example 3

In this example, different materials are present in each ofhole-transport layers A and C.

Compared with samples E5 and E6 according to the invention, referencesample V4 exhibits a significantly shorter lifetime (LT80 @ 60 mA/cm²)of 75 h compared with 175 h for E5 and 145 h for E6. The voltage of thetwo samples according to the invention is in each case lower at 4.0 V(E5) and 3.8 V (E6) compared with the reference of 4.2 V at 10 mA/cm².

Example 4

In this example, different materials are present in hole-transportlayers A and C.

Compared with sample E7 according to the invention, reference sample V5exhibits a shorter lifetime (LT80 @ 60 mA/cm²) of 105 h compared with E7of 125 h and a higher voltage of 3.8 V compared with 3.6 Vat 10 mA/cm².

Example 5

In this example, different materials are present in hole-transportlayers A and C.

Compared with sample E8 according to the invention, reference samples V6and V7 exhibit a shorter lifetime (LT80 @ 80 mA/cm²) of 65 h (V6) or 95h (V7) compared with 270 h for E8 and higher voltages of 4.6 V (V6) and4.1 V (V7) compared with 4.0 V for E8 at 10 mA/cm². The CIE colourcoordinates for all three samples were at (0.14/0.19).

By comparison, although the reference sample V11, which has a layercomprising compound HAT-CN instead of the p-doped interlayer, also hasvery low voltages of 3.8 V, it has, however, a shorter lifetime (LT80 @80 mA/cm²) of about 210 h.

Example 6

In this example, different materials are present in hole-transportlayers A and C.

Compared with reference sample V8, sample E9 according to the inventionexhibits a better lifetime (LT80 @ 60 mA/cm²) of 215 h compared with 155h and lower voltages of 3.7 V compared with 4.4 V.

Example 7

In this example, different materials are present in hole-transportlayers A and C.

Compared with samples E10 and E11 according to the invention, referencesample V9 exhibits a shorter lifetime (LT80 @ 60 mA/cm²) of 175 h and alower efficiency (EQE @ 10 mA) of 9.2% compared with 210 h and 9.7% forE10 and 255 h and 9.8% EQE for E11. Here too, the voltage of thereference sample is, at 4.0 V, higher than that of E10, at 3.7 V, andE11, at 3.8 V, at 10 mA/cm².

Example 8

In this example, different materials are present in hole-transportlayers A and C.

Compared with samples E12 and E13 according to the invention, referencesample V10 exhibits a shorter lifetime (LT80 @ 60 mA/cm²) of 165 hcompared with 450 h (E12) and 405 h (E13). Here too, the voltage of thereference sample is, at 4.3 V, higher than that of E12, at 3.96 V, andE13, at 3.7 V, at 10 mA/cm².

As shown in the above examples, the devices according to the inventionhave higher efficiency and preferably a longer lifetime than devices inaccordance with the prior art. Furthermore, the operating voltage of thedevices is preferably lower than in the case of devices in accordancewith the prior art.

The invention claimed is:
 1. An electronic device comprising anode,cathode and at least one emitting layer arranged between the anode andthe cathode, and at least one hole-transport layer A, comprising atleast one hole-transport material which is selected from triarylaminecompounds, at least one p-doped hole-transport layer B, comprising atleast one p-dopant and at least one hole-transport material matrix whichis selected from triarylamine compounds, at least one hole-transportlayer C, comprising at least one hole-transport material, which isselected from triarylamine compounds, where hole-transport layers A, Band C are arranged between the anode and the emitting layer, and wherehole-transport layer B is arranged on the cathode side of hole-transportlayer A, and hole-transport layer C is arranged on the cathode side ofhole-transport layer B and wherein hole-transport layers A, B and C andare directly adjacent to one another and the hole-transport layers A, Band C each comprise one or more identical or different monotriarylaminecompounds.
 2. The electronic device according to claim 1, wherein thedevice is selected from organic light-emitting transistors (OLETs),organic light-emitting electrochemical cells (OLECs), organic laserdiodes (O-lasers) or organic electroluminescent devices (OLEDs).
 3. Theelectronic device according to claim 1, wherein the anode comprisestungsten oxide, molybdenum oxide and/or vanadium oxide, and/or in that ap-doped hole-transport layer A′, comprising at least one p-dopant and ahole-transport material matrix, is arranged between the anode andhole-transport layer A.
 4. The electronic device according to claim 3,wherein hole-transport layers A, B, C and A′ each comprise one or moreidentical or different monotriarylamine compounds.
 5. The electronicdevice according to claim 3, wherein at least one of hole-transportlayers A, B, C and A′ comprises at least one compound of one of theformulae (I) to (VI)

where: Z is on each occurrence, identically or differently, N or CR¹,where Z is equal to C if a substituent is bonded; X, Y are on eachoccurrence, identically or differently, a single bond, O, S, Se, BR¹,C(R¹)₂, Si(R¹)₂, NR¹, PR¹, C(R¹)₂—C(R¹)₂ or CR¹═CR¹; E is O, S, Se, BR¹,C(R¹)₂, Si(R¹)₂, NR¹, PR¹, C(R¹)₂—C(R¹)₂ or CR¹═CR¹; Ar¹ is on eachoccurrence, identically or differently, an aromatic or heteroaromaticring system having 5 to 60 aromatic ring atoms, which may be substitutedby one or more radicals R¹; and R¹ is on each occurrence, identically ordifferently, H, D, F, Cl, Br, I, CHO, C(═O)R², P(═O)(R²)₂, S(═O)R²,S(═O)₂R², CR²═CR²R², CN, NO₂, Si(R²)₃, OSO₂R², a straight-chain alkyl,alkoxy or thioalkoxy group having 1 to 40 C atoms or a straight-chainalkenyl or alkynyl group having 2 to 40 C atoms or a branched or cyclicalkyl, alkenyl, alkynyl, alkoxy or thioalkoxy group having 3 to 40 Catoms, each of which may be substituted by one or more radicals R²,where one or more non-adjacent CH₂ groups may be replaced by R²C═CR²,Si(R²)₂, Ge(R²)₂, Sn(R²)₂, C═O, C═S, C═Se, C═NR², P(═O)(R²), SO, SO₂,NR², O, S or CONR² and where one or more H atoms may be replaced by D,F, Cl, Br, I, CN or NO₂, or an aromatic or heteroaromatic ring systemhaving 5 to 60 aromatic ring atoms, which may in each case besubstituted by one or more radicals R², or a combination of thesesystems; two or more adjacent substituents R¹ here may also form a mono-or polycyclic, aliphatic or aromatic ring system with one another; R² ison each occurrence, identically or differently, H, D, CN or analiphatic, aromatic and/or heteroaromatic hydrocarbon radical having 1to 20 C atoms, in which, in addition, H atoms may be replaced by D or F;two or more adjacent substituents R² here may also form a mono- orpolycyclic, aliphatic or aromatic ring system with one another; i is oneach occurrence, identically or differently, 0 or 1, where the sum ofall i is at least equal to 1; p is equal to 0 or 1; m, n are,identically or differently, 0 or 1, where the sum of m and n is equal to1 or
 2. 6. The electronic device according to claim 3, wherein each oneof hole-transport layers A, B, C and A′ comprises at least one compoundof one of the formulae (I) to (VI)

where: Z is on each occurrence, identically or differently, N or CR¹,where Z is equal to C if a substituent is bonded; X, Y are on eachoccurrence, identically or differently, a single bond, O, S, Se, BR¹,C(R¹)₂, Si(R¹)₂, NR¹, PR¹, C(R¹)₂-C(R¹)₂ or CR¹═CR¹; E is O, S, Se, BR¹,C(R¹)₂, Si(R¹)₂, NR¹, PR¹, C(R¹)₂-C(R¹)₂ or CR¹═CR¹; Ar₁ is on eachoccurrence, identically or differently, an aromatic or heteroaromaticring system having 5 to 60 aromatic ring atoms, which may be substitutedby one or more radicals R¹; and R¹ is on each occurrence, identically ordifferently, H, D, F, Cl, Br, I, CHO, C(═O)R², P(═O)(R²)₂, S(═O)R²,S(═O)₂R², CR²═CR²R², CN, NO₂, Si(R²)₃, OSO₂R², a straight-chain alkyl,alkoxy or thioalkoxy group having 1 to 40 C atoms or a straight-chainalkenyl or alkynyl group having 2 to 40 C atoms or a branched or cyclicalkyl, alkenyl, alkynyl, alkoxy or thioalkoxy group having 3 to 40 Catoms, each of which may be substituted by one or more radicals R²,where one or more non-adjacent CH₂ groups may be replaced by R²C═CR²,C≡C, Si(R²)₂, Ge(R²)₂, Sn(R²)₂, C═O, C═S, C═Se, C═NR², P(═O)(R²), SO,SO₂, NR², O, S or CONR² and where one or more H atoms may be replaced byD, F, Cl, Br, I, CN or NO₂, or an aromatic or heteroaromatic ring systemhaving 5 to 60 aromatic ring atoms, which may in each case besubstituted by one or more radicals R², or a combination of thesesystems; two or more adjacent substituents R¹ here may also form a mono-or polycyclic, aliphatic or aromatic ring system with one another; R² ison each occurrence, identically or differently, H, D, CN or analiphatic, aromatic and/or heteroaromatic hydrocarbon radical having 1to 20 C atoms, in which, in addition, H atoms may be replaced by D or F;two or more adjacent substituents R² here may also form a mono- orpolycyclic, aliphatic or aromatic ring system with one another; i is oneach occurrence, identically or differently, 0 or 1, where the sum ofall i is at least equal to 1; p is equal to 0 or 1; m, n are,identically or differently, 0 or 1, where the sum of m and n is equal to1 or
 2. 7. The electronic device according to claim 3, wherein at leastone of hole-transport layers A, B, C and A′ comprises at least onecompound of one of the formula (II) or (III)

where: Z is on each occurrence, identically or differently, N or CR¹,where Z is equal to C if a substituent is bonded; X is a single bond;Ar¹ is on each occurrence, identically or differently, an aromatic ringsystem having 5 to 60 aromatic ring atoms, which may be substituted byone or more radicals R¹; and R¹ is on each occurrence, identically ordifferently, H, D, F, Cl, Br, I, CHO, C(═O)R², P(═O)(R²)₂, S(═O)R²,S(═O)₂R², CR²═CR²R², CN, NO₂, Si(R²)₃, OSO₂R², a straight-chain alkyl,alkoxy or thioalkoxy group having 1 to 40 C atoms or a straight-chainalkenyl or alkynyl group having 2 to 40 C atoms or a branched or cyclicalkyl, alkenyl, alkynyl, alkoxy or thioalkoxy group having 3 to 40 Catoms, each of which may be substituted by one or more radicals R²,where one or more non-adjacent CH₂ groups may be replaced by R²C═CR²,C≡C, Si(R²)₂, Ge(R²)₂, Sn(R²)₂, C═O, C═S, C═Se, C═NR², P(═O)(R²), SO,SO₂, NR², O, S or CONR² and where one or more H atoms may be replaced byD, F, Cl, Br, I, CN or NO₂, or an aromatic ring system having 5 to 60aromatic ring atoms, which may in each case be substituted by one ormore radicals R²; R² is on each occurrence, identically or differently,H, D, CN or an aliphatic, aromatic hydrocarbon radical having 1 to 20 Catoms, in which, in addition, H atoms may be replaced by D or F; and pis equal to 0 or
 1. 8. The electronic device according to claim 7,wherein each one of hole-transport layers A, B, C and A′ comprises atleast one compound of one of the formula (II) or (III).
 9. Theelectronic device according to claim 8, wherein hole-transport layer Acomprises no p-dopant.
 10. The electronic device according to claim 1,wherein hole-transport layer A has a thickness of 100 to 300 nm.
 11. Theelectronic device according to claim 1, wherein hole-transport layer Acomprises no p-dopant.
 12. The electronic device according to claim 1,wherein the p-dopant is selected from quinodimethane compounds,azaindenofluorenediones, azaphenalenes, azatriphenylenes, I₂, metalhalides, metal oxides, transition-metal complexes and transition-metaloxides.
 13. The electronic device according to claim 1, wherein thep-dopant is present in hole-transport layer B in a concentration of 0.1to 20% by vol.
 14. The electronic device according to claim 1, whereinhole-transport layer C comprises no p-dopant.
 15. The electronic deviceaccording to claim 1, wherein hole-transport layer B comprises the samecompound as hole-transport material matrix as hole-transport layer Cdoes as hole-transport material.
 16. A light source in a lightingapplication which comprises the electronic device according to claim 1.17. A light source for use in a medical application which comprises theelectronic device according to claim
 1. 18. A light source in cosmeticapplication which comprises the electronic device according to claim 1.19. The electronic device according to claim 1, wherein each one ofhole-transport layers A, B, C and A′ comprises at least one compound ofone of the formulae (I) to (VI)

where: Z is on each occurrence, identically or differently, N or CR¹,where Z is equal to C if a substituent is bonded; X, Y are on eachoccurrence, identically or differently, a single bond, O, S, Se, BR¹,C(R¹)₂, Si(R¹)₂, NR¹, PR¹, C(R¹)₂-C(R¹)₂ or CR¹═CR¹; E is O, S, Se, BR¹,C(R¹)₂, Si(R¹)₂, NR¹, PR¹, C(R¹)₂-C(R¹)₂ or CR¹═CR¹; Ar¹ is on eachoccurrence, identically or differently, an aromatic or heteroaromaticring system having 5 to 60 aromatic ring atoms, which may be substitutedby one or more radicals R¹; and R¹ is on each occurrence, identically ordifferently, H, D, F, Cl, Br, I, CHO, C(═O)R², P(═O)(R²)₂, S(═O)R²,S(═O)₂R², CR²═CR²R², CN, NO₂, Si(R²)₃, OSO₂R², a straight-chain alkyl,alkoxy or thioalkoxy group having 1 to 40 C atoms or a straight-chainalkenyl or alkynyl group having 2 to 40 C atoms or a branched or cyclicalkyl, alkenyl, alkynyl, alkoxy or thioalkoxy group having 3 to 40 Catoms, each of which may be substituted by one or more radicals R²,where one or more non-adjacent CH₂ groups may be replaced by R²C═CR²,C≡C, Si(R²)₂, Ge(R²)₂, Sn(R²)₂, C═O, C═S, C═Se, C═NR², P(═O)(R²), SO,SO₂, NR², O, S or CONR² and where one or more H atoms may be replaced byD, F, Cl, Br, I, CN or NO₂, or an aromatic or heteroaromatic ring systemhaving 5 to 60 aromatic ring atoms, which may in each case besubstituted by one or more radicals R², or a combination of thesesystems; two or more adjacent substituents R¹ here may also form a mono-or polycyclic, aliphatic or aromatic ring system with one another; R² ison each occurrence, identically or differently, H, D, CN or analiphatic, aromatic and/or heteroaromatic hydrocarbon radical having 1to 20 C atoms, in which, in addition, H atoms may be replaced by D or F;two or more adjacent substituents R² here may also form a mono- orpolycyclic, aliphatic or aromatic ring system with one another; i is oneach occurrence, identically or differently, 0 or 1, where the sum ofall i is at least equal to 1; p is equal to 0 or 1; m, n are,identically or differently, 0 or 1, where the sum of m and n is equal to1 or
 2. 20. The electronic device according to claim 16, wherein atleast one of hole-transport layers A, B, C and A′ comprises at least onecompound of one of the formula (II) or (III)

where: Z is on each occurrence, identically or differently, N or CR¹,where Z is equal to C if a substituent is bonded; X is a single bond;Ar¹ is on each occurrence, identically or differently, an aromatic ringsystem having 5 to 60 aromatic ring atoms, which may be substituted byone or more radicals R¹; and R¹ is on each occurrence, identically ordifferently, H, D, F, Cl, Br, I, CHO, C(═O)R², P(═O)(R²)₂, S(═O)R²,S(═O)₂R², CR²═CR²R², CN, NO₂, Si(R²)₃, OSO₂R², a straight-chain alkyl,alkoxy or thioalkoxy group having 1 to 40 C atoms or a straight-chainalkenyl or alkynyl group having 2 to 40 C atoms or a branched or cyclicalkyl, alkenyl, alkynyl, alkoxy or thioalkoxy group having 3 to 40 Catoms, each of which may be substituted by one or more radicals R²,where one or more non-adjacent CH₂ groups may be replaced by R²C═CR²,C≡C, Si(R²)₂, Ge(R²)₂, Sn(R²)₂, C═O, C═S, C═Se, C═NR², P(═O)(R²), SO,SO₂, NR², O, S or CONR² and where one or more H atoms may be replaced byD, F, Cl, Br, I, CN or NO₂, or an aromatic ring system having 5 to 60aromatic ring atoms, which may in each case be substituted by one ormore radicals R²; R² is on each occurrence, identically or differently,H, D, CN or an aliphatic, aromatic hydrocarbon radical having 1 to 20 Catoms, in which, in addition, H atoms may be replaced by D or F; and pis equal to 0 or
 1. 21. The electronic device according to claim 20,wherein each one of hole-transport layers A, B, C and A′ comprises atleast one compound of one of the formula (II) or (III).
 22. Theelectronic device according to claim 21, wherein hole-transport layer Acomprises no p-dopant.
 23. An electronic device comprising anode,cathode and at least one emitting layer arranged between the anode andthe cathode, and at least one hole-transport layer A, comprising atleast one hole-transport material which is selected from triarylaminecompounds, at least one p-doped hole-transport layer B, comprising atleast one p-dopant and at least one hole-transport material matrix whichis selected from triarylamine compounds, at least one hole-transportlayer C, comprising at least one hole-transport material, which isselected from triarylamine compounds, where hole-transport layers A, Band C are arranged between the anode and the emitting layer, and wherehole-transport layer B is arranged on the cathode side of hole-transportlayer A, and hole-transport layer C is arranged on the cathode side ofhole-transport layer B and wherein hole-transport layers A, B and C andare directly adjacent to one another and wherein the hole-transportlayer A comprises the same compound as hole-transport material ashole-transport layer A′ does as hole-transport material matrix.
 24. Anelectronic device comprising anode, cathode and at least one emittinglayer arranged between the anode and the cathode, and at least onehole-transport layer A, comprising at least one hole-transport materialwhich is selected from triarylamine compounds, at least one p-dopedhole-transport layer B, comprising at least one p-dopant and at leastone hole-transport material matrix which is selected from triarylaminecompounds, at least one hole-transport layer C, comprising at least onehole-transport material, which is selected from triarylamine compounds,where hole-transport layers A, B and C are arranged between the anodeand the emitting layer, and where hole-transport layer B is arranged onthe cathode side of hole-transport layer A, and hole-transport layer Cis arranged on the cathode side of hole-transport layer B and whereinhole-transport layers A, B and C and are directly adjacent to oneanother and wherein the hole-transport materials of hole-transportlayers A and C are different.